Queen Elizabeth is expected to attend the Remembrance Sunday ceremony at the Cenotaph, the focal point of the nation's homage, on November 14, said Omid Scobie.
He said the Queen has returned to Windsor Castle after a private weekend away at her Sandringham estate in Norfolk.
Last month the Queen spent a night in hospital for the first time in years for what Buckingham Palace termed 'preliminary investigations'.
The world's oldest and longest-reigning monarch cancelled an official trip to Northern Ireland.
The head of state, who next year celebrates 70 years on the throne, is known for her robust health and the last time she is thought to have spent a night in hospital was in 2013 when she was suffering from symptoms of gastroenteritis.
She had a successful surgery to treat an eye cataract in 2018, and also had a knee operation in 2003. However, royal officials are loathe to discuss health issues in general, saying medical matters are private.
Earlier this year, Prince Philip, her 99-year-old husband of more than seven decades, died at Windsor Castle.